On May 2, 10:39 am, "Robert M. Gary" wrote:
On May 2, 7:18 am, C J Campbell
wrote:

The 172 may be able to stand the G forces, but that is not the only
limitation. The carburetor only works when right side up, for example.

Is that true? I can understand that the float would run out of gas
after a bit but I don't see how the carb itself would care about the
G's. In the Aeronca we were able to maintain inverted flight for more
than a couple of seconds before the engine would stop. The carb is
already on the bottom of the engine and the fuel/air mixture travels
up the intake via the massive suction of the intake stroke.

-Robert

Got to understand the carburetor. The gasoline is in a chamber,
its level kept constant by the float valve. The fuel leaves the
chamber by a small hole ("jet") in the bottom of that chamber,
travelling through the nozzle to be sprayed into the airflow. Turn the
carb over and the gasoline goes to the top of the chamber and the jet
gets nothing but fumes. The engine will quit. If the pilot is able to
maintain at least some fraction of positive G loading in the maneuver,
the fuel will stay in the bottom of the chamber and the engine will
run.

Dan